Cutting machine



June 17, J; c DRADER CUTTING MACHINE Filed April 9, 19:54 8 Sheets-Sheet 1 0 Q A g 4 545 K IL j,4 J J I 6 26 26 4/ MM Z ..-I' INVENTOR. 44 J0 567% CT Zrdder:

ATTORNEYS.

June 17, 1941. DRADER V 2,245,907

CUTTING MACHINE Filed April 9, I934 s Sheets-Sheet 2 I Josey/7 C. flrader ATTORNEYS.

June 1-7, 1941-.

,J. C. DRADER CUTTING MACHINE Filed April 9, 1934 8 Sheets-Sheet 3 INVEN TOR.

m a E u NR 1Q 0Q N x k m l UNITY. w I I w w m \JQ Jase Z77 C Brad??? June 17, 1941. J. c DRADER I 2,245,907

. CUTTING MACHINE Filed April 9, 1934 8 Sheets-Sheet 4 r T //6 A32 E-- ,m

- ATTORNEYS.

June 17, 1941. J. c. DRADER CUTTING MACHINE Filed April 9, 1934' 8 Sheets-Sheet 5 DA H INVENTOR- Frdaen 1 J0 sqp/r v BY ATTORNEYS.

June 17,1941. J, c, DRADER cumme MACHINE Filed April 9. 1934 8 Sheets-Sheet 6 INVENTOR Josey/7 6". Brads)? ATTORNEY-5.

June 17, 1941.

.I. c. DRADER CUTTING MACHINE Filed April 9, 1934 8 Sheets-Sheet 7 'IIHIIIIII [H1 [IIIHHIIIIHIII teeth sides and is necessary to surfaces.

Patented June 17, 1941 UNITED STATES PATENT OFFICE 2,245,907 CUTTING MACHINE Joseph C. Drader, Detroit, Mich. Application April 9, i934, Serial No. 719,646 6 Claims. (01. 90-4) My invention relates to machines and particularly to a machine for accurately finishing worm gear elements to be in surface-mated relation.

The present invention deals with a machine for finishing worm gearing of the globoidal type having threads in surface-mated relation which reduces heat and friction loss and provides long life. Such gear elements and the method of producing the same have been illustrated, described and claimed in the patents to Cone *No. 1,683,163, No. 1,751,540, No. 1,822,800, and No. 1,885,686. The present machine is employed primarily for producing a small worm gear unit but it is to be understood that the principles and inventions embodied in the machine are not limited to wormgear elements of a particular size but maybe emwheel at a low rate of speed relative to the operand the cutters are rotated at a relative lower ployed on any size of'elements. The principles are the same in any instance.

In practicing my invention, I employ a machine having a spindle to receive a gear element and for driving it in rotation in synchronism with the driving of the spindle for the cutting tool or tools, which is a hob in, the case of the worm wheel and a cutter in the case of the worm. The tools are first automatically fed into proper depth and thereafter are additionally rotated to eilect a side cutting operation on the teeth or thread of the worm elements.

The additional rotation of the hob causes'the cutting edge to shiit due to the lead of the thread to thereby finish the side of teeth of the worm, while in the case of the worm the additional r0- tation of the cutter causes the sidesof the teeth to be advanced into the thread to thereby finish the sides of the thread to accurate dimensions. Itis needless to say that in'both instances the teeth of the hob and the cutter are narrower than the width of the ultimate gap-to be formed which is necessary to provide sufiicient stock for a dressing operation efiected by the additional rotation of the tools.

It is well known thatg the in-feeding" of a tooth of a tool into a globoidal worm element will deform the sides of the gaps so that they are not true surfaces and will not mate with the teeth of a worm wheel to provide surface engagement.

The additional rotational movement of the tool eflects a finishing operation to provide mating The machine is so constructed that the its "tive rotationof the elements, that between the hob and worm wheel and between the cutters and the worm, can be changed. In the cutting of the worm wheel it is necessary to drive the worm the thread and of the cut grooves drive the worm speed. The relative rotation, however, is the same and through the interchanging of the driving gears for the tool and work spindles the change in relation of the rotation of the work and tool a specified above, is eifected. In this manner, a single machine may be'changed over to produce first worms and then worm wheels and if separate worm and worm wheel machines are employed, similar gearing will be provided therein which are interchangeable.

After the work is assembled, the machine is started through the operation of a clutch. The tools and work operate in timed relation and the tools are automatically advanced into the work until a required depth is reached after which the tools are additionally rotated or retarded a predetermined amount to advance the cutting edges into the sides of the grooves formed. through the initial advancement of the tools. Thereafter, the tools are automatically drawn apart and away from the work andthe machine stopped. Means are provided which permits the stopping of the machine at any point in its cycle of operation and certain adjustments are provided on the machine to permit the tools to be set in aligned relation to each other. The tools are preferably employed one on each side of the gear elements and, are rotated to cut on opposite sides of threads being machined. 'In this manner the torque on the spindle the work and the tools is balanced and finer machining operations are thereby produced.

Accordingly, the main objects of my invention are to provide a machine which is simple in construction and which automatically feeds one or more tools into-the work to a proper depth and to thereafter feed sidewardly to dress the sides to accurate dimensions, after which the tools aremoved away from the work and the machine stoppedito provide a. machine having tools on each side of the work elements to be advanced into the work and thereafter operate on opposite sides of the groove to thereby balance the torque produced by the cutting operation; to construct a machine having gears of such relation that they may be interchanged to wheel at low speed and the hobbing tools athigh speed or the worm at high speed and the cutters at low speeds being relative; to provide a machine which is completely automatic in operationfrom 7 low speed, the high and chines with extreme rapidity.

the starting to the finishing operation including the movement of the tools away from the work; to provide a. base whereon several of the machines may be. mounted and operated from a single power source to utilize a single operator for a battery of such machines; and, in general, to provide a machine for finishing the worm elements of globoidal type which is simple in construction, economical of manufacture, which is extremely simple in operation, which machines with a high degree of accuracy, and which ma- Other objects and features of novelty of my invention will be either specifically pointed out or will become apparent when referring, for a better understanding of my invention, to the following description taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a perspective view of a base having a plurality of machines embodying my invention mounted thereon driven from a common source;

Fig. 2 is an enlarged broken sectional view of Fig. 22 is a diagrammatic view of structure, similar to that illustrated in Fig. 21, but rearranged to produce the proper speed and driving relation between the worm wheel and hobs.

In Fig. 1, I have illustrated an elongated base 25 which has three machines 26 mounted thereon to facilitate the operation of a plurality of the machines by a single operator and the driving of the work spindles and the tools illustrated on the machines of Fig. 1;

Fig. 3 is an enlarged plan view of one of the machines illustrated in Fig. 1;

Fig. 4 is an enlarged sectional view of the work spindle illustrated in Fig. 2;

Fig. 5 is a side view of the structure illustrated I in Fig. 4 with parts in section;

Fig. 6 is a sectional view of the driving means for the tool spindle;

Fig. '7 is a sectional viewof the structure illustrated in Fig. 6, taken on the line 1-1 thereof;

Fig. 8 is a sectional view of the structure illustrated in Fig. '7, taken on the line 8-8 thereof;

Fig. 9 is a view of gearing for controlling the operation of various elements of the machine.

with the supporting portions therefor broken away;

Fig. 10 is a view of a portion of the structure illustrated in Fig. 6, showing a modified form thereof.

Fig. 11 is a sectional view of the structure illustrated in Fig. 9, taken on the line llll thereof, Fig, 12 is a sectional view of a worm wheel and two hobs in finishing relation;

Fig. 13 is a view in elevation of one form of worm wheel cut by the hobs;

Fig. 14 is a worm wheel, similar to that illustrated in Fig. 11, the teeth of which have a shorter lead;

Fig. 15 is a view of structure partly in section employed for advancing the tools into the work and for controlling the operation of the machine;

Fig. 16 is an enlarged sectional view of the structure illustrated in Fig. 15, taken on the line l6l6 thereof;

Fig. 1'7 is an enlarged sectional view of the structure illustrated in Fig. 15, taken on the line i1-i1 thereof;

Fig. 18 is a perspective view of structure similar to that illustrated in Fig. 2, showing the hobs and a worm wheel substituted for the cutters and. worm;

Fig. 19 is an enlarged sectional view of a portion of the structure illustrated in Fig. 4, modified to support the worm wheel;

Fig. 20 is a plan view of the worm and cutters, showing their relation to each other.

Fig. 21 is a. diagrammatic view of the gearing of the machine disclosing the operating and speed relation of the various gear elements for driving the cutters to produce worm elements, and

construct similar machines for cutting the worm wheel. Both types of machines could be mounted on the same base. In this manner, substantially the same castings and driving units are employed and assembled in slightly different manner to provide machines which will cut the different worm gear elements as wi1l,be explained fully hereinafter. The machines are operated by a motor 21 which drives the belt and pulleys 28 for operating a shaft 29 which extends along the base to drive each of the machines through a bevel gear 31, as illustrated in'Fig. 3. The bevel gear 3! drives a similar gear 32 to operate a shaft 33 in which a clutch 34 is provided. The shaft 33 operates through a pair of driving gears 35 to .drive a shaft 36 which operates through a train of'gears 31 to operate a shaft 38 in timed relation to the shaft 36.

Each machine 26 is provided with a base 41 in which spindle housings 42 of opposite hand are mounted in ways 43 for movement normal to the spindles. A housing 44 contains a work supporting spindle 45 steadied at its upper end by a rest 46, as illustrated more clearly in Fi 2, which is mounted in a reciprocable element 1 retained in a support 48. A shaft 49 operated by a handle 5| moves the element 41 in reciprocation and a locking shaft 52 actuated by a handle 53 retains the element 41 in moved position. In Fig, 2, I have illustrated a worm 54 mounted on the spindle 45 and retained by the element 46 in fixed aligned relation The housings 42 are provided with spindle receiving shafts 55 in which the cutting tools56 are retained for rotational movement.

Referring to Figs. 4 and 5, I have illustrated the work supporting structure in section wherein the work receiving spindle 45 ismounted on the end of a shaft 51 which is retained for rotational movement in suitable bearings 58 within the housing 44 having a worm wheel 59 on its lower end secured thereon by a suitable key 6| and nut 62. The worm wheel 59 meshes with a worm 63 which is mounted on a shaft 64. g

The shaft 64 is mounted in suitable bearings 65 to be driven by the shaft 66 which is keyed thereto. A suitable casing 61 covers the worm wheel unit and is sealed to retain a lubricant therein. It will be notedthat the element 41 is hollow to receive aspring 68 retained by an adjustable stop 69 which may be regulated to adjust the tension on the work-steadying portion 46. The element 46 is hollow to receive the shaft end 11 of the worm 54, the element 45 being likewise recessed and slotted to receive the other shaft end of the worm which is provided with a land which. registers in the slot to have the worm.

section in Figs. 9 and 11 wherein the shaft 36 drives through a gear 13 to operate similar gears 14, 15 and 16, which latter gear drives the shaft 38. The gear 14 drives. through timing gears 83, 11 and 18, the shaft '66 which,as has been pointed out hereinabove, drives the worm 63 of the work-supporting spindle. In this manner the spindle is driven at a predetermined speed relative to the rotation of the tools.

Connected also to the shaft 38 is a gear 19 in mesh with a gear 8I which operates a shaft 82 for effecting the actuation of the spindle housings 44 in reciprocation in a manner which will be explained more fully hereinafter. The shaft supporting the gear 14 operates the timing gear 83 to drive through the idler "gear 11, the gear 18 which drives the shaft 66. change of the gears 11, 18 and 83 the rotation of the work is regulated in timed relation to the rotation of the cutting tools.

In Figs. 6, '1 and 8, I have illustrated the tool spindle housings 42 as comprising a dovetailed slide portion 84 carrying a bearing supporting housing 85 in which ball bearings 86 support a hollow worm and shaft 81 which is mounted over the shaft 38. It is to be understood that the same structure as illustrated in Fig. 6, is also provided relative to the shaft 36 which extends beyond both ends of the housing. A key 88 is carried on the inner surface of the hollow worm and shaft 81 which is mated in a vided in the shaft 38 to cause the worm to rotate with the shaft and to be slidable axially thereof. One end of the bearing supporting housing 85 is closed by a cam following plate 9| having sealing element 92 therein while the opposite end is closed bya spring engaging plate 93 likewise having a sealing element 92 therein. the bearing receiving housing 85 forms a well for keyway 89 pro- Through the inter-- In this manner receives the tool holder retaining a lubricant for lubricating the bearings Y and the worm elements.

A spring housing 94 is secured over one end of the shaft 38 and supported to the end of the slide housing 84 by suitable bolts 95. The housing 94 retains a spring plate 96 against a plurality of springs 91 which engage the spring plate 95 for forcing the worm and shaft 81 toward a cam 98.

The cam 98 is bearing in a suitable projection portion 99 of the housing 84 having an internal gear I M formed therein which is of the same diameter as an internal gear I02 formed in the cam 98 having one more or less teeth therein for causing the advancement of the cam due to the operation of a gear I03 which is mated with teeth I04 on the shaft 38. The teeth are so constructed as to provide a ratio of 300 or 400or more to one. turn once to 300 or 400 revolutions of the shaft 38. The cam plate 9I carries a roller I05 with which the cam surfaces I06 of the cam 98 engage. I I

As shown in the drawings, the cam has been operated to cause the axial movement of the worm wheel 81 to the left, as viewed in Fig. 6, and as soon as the roller I05 passes over the high portion of the cam, the-springs 91 will cause the worm to be movedto the right, all for a purpose which will be explained hereinafter.

In Fig. 10, I have illustrated the same construction as in Fig. 6 with the exception that the cam plate 9| has been drawn into engagement with the housing 84 and retained in firm fixed relation therewith bya plurality of bolts I01. In this construction it will be noted that the roller I05 is disengaged from the high portion of the cam surface I 060i the cam 98 and in this manner the worm and shaft 81 is retained in 'fixed position out of a position to be operated axially That is to say. the cam 98 will" 3 by the cam. Under certain conditions as will be ,pointed' out hereinafter the operation of the machine without the 81 may be desired.

In Fig. 8, I have illustrated a section of the structure illustrated in Fig. 6 wherein the worm 81 drives a worm wheel I08 for driving a shaft I09 in rotation. The shaft I09 is hollow and 55. The tool holder 55 passes entirely through the shaft I09 having a nut I II on the tool receiving end and nut I I2 on the opposite end whereby the projection of the tool from the housing 44 may be regulated. A rod H3 is threaded tothe end of the tool and passes through the holder 55 to retain the tool fixed to the holder. A head 'II4 is provided on the rod by which the rod I I3 is turned to draw the tool in firm relation to the holder 55. Suitable ball bearings IIB are provided for supporting the shaft while a key and keyway II5 retains the element 55 in driving relation to the hollow shaft I09. A spacing element H1 is provided on the shaft for positioning the worm. wheel I08 thereon against endwise movement. The worm wheel I08, as illustrated in Fig. 8, is mounted on a collar II8 having ears II9 thereon engage able by screws I2I: carried by the worm wheel. Through the adjustment of the screws the worm wheel is moved relative to the hollow shaft I 09 to adjust the shaft in rotation for positioning the hobs relative to each other and the Work. When the cam 98 is not employed, as in the construction illustrated in Fig. 10, the shaft 38 may be split and provided with an adjustable connecting element to provide a greater degree of adjustment to the tools. However, in view of the synchronized relation of this connecting element must be accurately set and not employed when the cam 98 is utilized.-

'to permit access to the screws I2I for effecting the adjustment.

For advancing the tools through the movement of the tool spindle housings 42 and the slide 84, I have provided a mechanism, illustrated in Figs. 15, 16 and 17, which automatically effects such advancement in opposite direction to feed the tools toward the work. It has been pointed out hereinbefore that the shaft 38 operates a .gear 19 for driving a gear 8| and shaft 82. Through the operation of the shaft 82, the rotation of a cm I 23 is effected. The gear 8I drives the shaft 82 supported in bearings I24. The shaft is provided with teeth I25 in mesh with a gear I26 which operates on two internal gears I21 and I28 one of which has one more or less teeth than the other so that during each revolution of the gear I26 the cam I23 will be advanced one tooth so that several .hundred revolutions of the shaft 82' will be necessary 'to produce a single rotation of the cam I 23. A cam following roller I29 engages the surface of the cam I23 against which it is biased by a spring I3I the tension of which may be regulated through the adjustment of a nut I32 on a screw I33. A double sector gear element I34 is supported on a center I30, having the teeth I35 at the ends, meshing with racks I36 disposed on each side thereof. The racks are secured to the slides as illustrated in Fig. 3 by suitable clamping nuts I 31. Lead screws I38 are provided on the racks I36 cooperating with the slides 84 in such manner that when the nuts I31 are loosened the screws I 38 may be adjusted to position the slides 84 relative to each other axial movement of the worm the tools and work,

and the center of the shaft 51, after which the nuts I31 are tightened.

The cam I23 is constructed to have the slides 84 retracted from the work when the roller I29 is in the lowermost portion M! of the cam surface and to be fed into the work as the roller advances up the sloping surface I42. The slides 84 will be retained in this position as the roller rides over the dwell portion I43 of the cam. During the time the roller is contacting the sloping surface I42 the tools are fed into the work to desired depth. They are retained in this position as the roller rides on the surface I43, during which time the cutting edges of the tool are advanced to widen the gap initially formed, to produce accurate worm gear elements as will be explained more fully hereinafter.

The clutch 34 is of standard clutch plate type and unites the shaft 33 with the shaft of the gear 32 through the rearward movement of an operating rod I44. The rod is supported on a clutch operating bell crank I45 which is pivoted at I46 and has an arm I41 carrying clutch engaging pins I48 which operate the clutch. When the rod I44 is moved rearwardly, as illustrated in Fig. 3, the bell crank is rotated in a counterclockwise direction permitting the detent I48 to engage a notch I49 in the end of the other arm I5I of the bell crank. In this manner the clutch is locked in engaged position and the machine will be driven through the gears 3I and 3'2. This operation will cause the rotation of the work and tools in predetermined synchronism and the operation of the cam I23 and the cam 98.

During the initial portion of the operating cycle the cam 98 engages the roller I05 on the dwell portion I06 and no.advance movement of the worm 81 is effected thereby. During the time the cam I23 is advancing, the one rack I36, through the contact of the roller I29 with the sloping surface I42, operates through the gear sector I34 to drive the opposite rack I35 in the opposite direction to thereby cause the slides 84 to be advanced in opposite direction toward the work. In this manner, the tools are fed into' the work until the proper depth of cut is obtained, to be retained in this position by the roller I29 in contact with the dwell surface I43 of the cam I23. At this time the cam roller I05 is engaged by the projecting surface of the cam 98 to cause the worm elements 81 to be shifted axially to thereby rotate the tool supporting shaft and tools, to cause the side feeding of the cutting edges. In the case of cutters for the worm one of the cutting tools will be rotated clockwise while the other onewill be rotated counter-clockwise to thereby cut the opposite sides of the thread of the worm by widening the gap to desired dimensions and to produce true thread form. It will be noted that the tools are disposed in the opposite sense so that the same rotation of the tools produce the clockwise and counter-clockwise movements.

In the case of the hobs,'however, the rotation of the tools is in the same direction since they are operating on opposite sides of the worm wheel.

The advancement of the lead of the thread of the hobs caused by the increment of rotation will cause the side cutting, to widen the gap and produce true form. The right hand side of the tooth on one side of "the worm wheel will be the left hand side on the opposite side so that it is necessary to cut on the right hand side of teeth on opposite sides of the worm wheel to cut on opposite sides of the teeth. For this reason it is necessary to rotate the hob shafts in opposite directions to have the cutting edges advanced in the same direction. This may be effected by reversing the mechanism illustrated in Fig. 6 changing it from one end to the other or by having the cam surface and dwell portion of the cam changed to have the side feeding effected on the lower portion of the cam surface.

The particular association of the hobs with the worm wheel is illustrated in Figs. 12, 13 and 14. In Fig. 12 it will be noted that a hob I53 on one side of the worm wheel I54 has been turned to advance the cutting edges in the side of the worm teeth toward the stem of the hob while the hob I55 on the opposite side of the worm wheel has been turned in the opposite direction to advance the cuttingedges in the opposite side of the teeth toward the end of the hob opposite to the stem. The worm wheel is illustrated in Fig. 14 having a definite and appreciable helix angle or lead to the teeth, while in Fig. 13 a worm wheel I56 is illustrated wherein the teeth have a long or slow lead. This latter type of worm wheel is illustrated to show when the operation of the cam 98 may be omitted, as in the view of Fig. 10, where side feeding may be eliminated. This is due to the fact that the in-feeding of the cutting teeth, on a worm wheel where the teeth are substantially straight, the teeth are not deformed materially and sufficient surface contact will be provided without the side feeding. When the teeth, however,- are disposed at a greater helix angle than that illustrated in Fig. 13, the side feeding will be necessary to compensate for the deforming of the sides by the in-feeding of the hob teeth.

After the side feeding of the tools, the roller I29 drops from the dwell portion I43 into the recess I4I to retract the rack elements I36 and the slides 84. During this retracting movement a second detent I51 engages the detent I48 to move it from the notch I49 in the arm I5I of the bell crank I45. After the detent I48 clears the notch I49, a projection I58 on the arm I5I moves the detent I51 out of contact with the detent I48 through the actuation of a spring pressed plunger I59. In this manner the detent I48 is again available to engage the notch I49 when the bell crank I is again rotated to enage the clutch 34. The detent I51 rides over the detent I48 during the advance movement of the slides 84 to be biased into the position illustrated, one to engage the detent I48 on the return movement of the slides 84, to cause the release of the clutch 34 and the stopping of the machine. The work element is then removed and new work elements inserted, after which the longitudinal movement of the rod I44 causes the arm I5I to rotate in .a counter-clockwise direction and to be engaged by the detent I48 urged by the spring I6I.

A projecting element I62 is provided on the detent I48 for the purpose of releasing it at any time so that the machine may be stopped within its cycle of operation. This projecting element extends through a slot I63 in the base 26 and is provided with a notch I which engages the frame and retains the detent out of engagement with the notch I49. It will be noted particularly in Figs. 15 and 17 that a spring I 64 is provided for urging the detent I51 in a counter-clockwise direction.

In Fig. 18 I have illustrated two hobs operating on a worm wheel employed in place of the cutting tools illustrated in Fig. 2 operating on slot is reached after 560 revolutions while,

The worm elements 59 tion between the pin I66 and the worm wheel. The end 46 of the reciprocable element 41 is similar to that illustrated in Fig. 4 for-engaging the end of the pin I66 and the Worm wheel for steadying them and retarding. the machining operation.

The operation of the machine for cutting worm wheels by the hobs is similar, except for speeds, to that above described relative to the worm and cutters. The relation of the cutters to the worm is illustrated in Fig. 20 where the cutters are fed toward each other until the depth of the which they are rotated to cut the sides of the slot to proper form and the slot to desired width. The worms and worm wheels cut in this manner have accurate mating surfaces which reduce wear and friction and provide long life to the elements.

In Figs. 21 and 22, I have illustrated diagramrelation to each other.

alignment during I ways are revolved at a matically the speed ratios of the elements to illustratethe novel feature of of certain of the elements for producing the difference in speed ratios. In Fig. 21, I have illustrated the machine constructed to operate on a I worm by ,;a pair of cutting tools, while in Fig. 22

I have illustrated a pair of hobs operating on a worm wheel. The relative rotation of the cutters and elements are naturally reversed, in the present instance the worm and Worm wheel have a ratio of 14 to 1, that is to 'say, the worm turns 14 times to the worm wheels single operation. This same ratio obtains relative to the tools and the work elements. In other words, the cutting tools operating to produce the Worm will rotate once during the time the worm makes 14 revolutions, while in the case of the hobs, the worm wheel will rotate once while the hob rotates 14 times. In the first instance the tool rotates slowly relative to the work while in the latter case the reverse is true.

The machines are geared up in such manner that the worm cutting tools and the worm wheel are rotated 70 revolutions .per minute while the hobs and the worm are rotated 980 revolutions per minute. When cutting the worms, the pulleys and belt 28 are so related as to produce 400'revolutions per minute to the shaft 29, while in the case of cutting the worm wheels, the pulleys and belt 28 are such as .to produce a speed to the shaft 29 of 560 revolutions per minute. Upon passing through the gears 31 and 32, the shafts 33 and 36, in the case of the worm, are driven at in the case of the worm revolutions per minute. and 63 for driving the work and the'elements I66 and 81 for driving the tool spindles have a .4 to 5 and 8 to 1 ratio, respectively, and are interchangeable as will be noted in the figures. In this manner, the relative speed of 70 and 980 revolutions per minute are provided to the tools and work in one instance and the work and tools in the other instance. Further timing for effecting the speed changes wheel, are driven 7.84

interchangeability parent to those skilled 5 gears 83, 18 and 11 as illustrated in the figures.

In this manner the number of different gears required. for the two machines is materially reduced, and very little change is required in one machine to produce one of the other type.

Substantially all of the gears, spindles, shafts, control mechanism, the base and frame are the same on both machines so'that very little change is required to produce machines of either type. By employing two scribed, the gap widening is effected by having each tool operate on a diiferent'side of the gap at the same time to produce true curved forms. The operation of the two tools on opposite sides of the work element balances the torque thereof,

releases the strain on the tools and the work element and the driving and supporting elements of the machine. Since the worm elements alparticular speed relative to each other, the gear ratio set up for one machine may apply, Figs. 21 and 22, to the other and thereby eliminate different structures and layouts for the two machines. The renewal of parts required by the machines is materially reduced and the machine is extremely simplified.

While I have described and illustrated but a single embodiment of my invention, it will be apchanges, omissions, additions and substitutions may be made therein without departing from the spirit and scope of my invention as set forth in the accompanying claims.

I claim as my invention:

1. A machine for cutting worm elements 'pro-.

' vided with a work spindle for driving a. worm eleare obtained through the'interchanging of the ment, two tools disposed in spaced relation about the element and having cuttingedges narrower v than full mating width, means for moving said tools radially toward the element during the machining operation to cut a gap therein to proper depth, and means for thereafter side'feeding the cutting edges of the tools so that said edges cut on respectively opposite sides of the gap to widen the gap.

2. A machine for accurately cutting worm elements which includes, in combination, means for supporting and driving a worm element, means for supporting and rotating two tools in spaced relation about the worm element, said tools hav-- ing cutting edges narrower than full mating width, means for radially advancing said tools into the worm element during a machining operation to cut a gap of predetermined depth therein, and means for thereafter simultaneous- 1y sidefeeding the cutting'edgesof the tools so that said edges cut on respectively opposite sides of the gap to widen the gap initially cut.

3. A machine for accurately cutting worm elements which includes, in combination, means for supporting 'and drivinga worm element, means for supporting and rotating two tools in spaced relation about the worm element. said tools having cutting edges narrower than full mating width, means for advancing said tools into the worm radially of the worm element during the machining operation to out the proper depth of gap in the worm element, means for thereafter side feeding the cutting edges of the tools so that said edges cut on respectively opposite sides of the gap by simultaneously cutting away the opposite sides of the worm element thread to pro-\- duce true curved forms, and means controlled in accordance with said side feeding action for tools in the manner above de-.

in the manner as illustrated in in the art that various.

thereafter withdrawing the tools from the worm element and stopping the machine.

4. A machine for cutting threads in one element of a worm couple of the enveloping type, comprising a spindle for rotatably supporting said one element, a plurality of cutting tools of a formcorresponding to that of the other element of said couple but having teeth of narrower width than required for full mating contact with the threads on said one elementwhen finished, a pair of tool spindles arranged to support said tools relative to said one element in positions radially spaced from but otherwise correspondingv to positions of said other element when coupled with said one element and with the individual tools in spaced relation circumfere entially of said one element, means for driving said worm element and tool spindles in rotation at rates corresponding to mating rates of said elements of said couple, means effective during said rotation for feeding said tool spindles radially toward said one element to positions of center distance spacing from said one element corresponding to proper center distance spacing between saidelements of said couple to cause ments of said couple, means effective during said rotation for feeding said tool spindles radially toward said one element to positions of center distance spacing from said one element corresponding to proper center distance spacing between said elements of said couple to cause said tools to form gaps in said one element of full depth and having angularly extending sides, and means for thereafter, actuating said tool spindles to effect a side feed movement of the teeth of the associated tools so that one tool widens the gaps at one side thereof, and changes the angular relation of said one side and so that the other tool widens the gaps at the other side thereof and correspondingly changes the angular relation of said other side.

6. A machine for cutting threads in one element of a worm couple of the enveloping type,

said tools to form gaps in said one element of full v depth and having angularly extending sides, and means for thereafter actuating said tool spindles to effect a side feed movement of the teeth of the associated tools so that one tool widens the gaps at one side thereof and changes the angular relation of said one side and so that the other tool widens the gaps at the other side thereof and correspondingly changes the angular relation of said other side. r

5. A machine for cutting threads in one element of a worm couple of the enveloping'type, comprising a spindle for rotatably supporting said one element, a plurality of cutting tools of a form corresponding to that of the other element of said couple but having teeth of narrower width than required for full mating contact with the threads on said one element when finished, a pair of tool' spindles arranged to support said tools relative to said one element in positions radially spaced from but otherwise corresponding to positions of said other element when coupled with said one element and with the individual tools in diametrically opposed relation relative to said one element, means for driving said worm element and'tool spindles in rotation at rates corresponding to mating rates of said elecomprising a spindle for rotatably supporting said one element, a plurality of cutting tools of a form corresponding to that of the other element of said couple but having teeth of narrower width than required for full mating contact with the threads on said one element when finished, a pair of tool spindles arranged to support said tools relative to said one element in positions radially spaced from but otherwise corresponding to positions of said other element when coupled with said one element and with the individual tools in spaced relation circumferentially of said one element, means for driving said worm element and tool spindles in rotation at rates corresponding to mating rates of said elements of said couple, means effective during said rotation for feeding said tool spindles radially toward said one element to positions of center distance spacing from said one element corresponding to proper center distance spacing between said elements of said couple to cause said tools to form gaps in said jpne element of full depth and having angularly extending sides, and means actuated by said driving means and rendered effective at the conclusion of said radial feed movement for actuating said tool spindles to effect a side feed movement of the teeth of the associated tools so that one tool widens the gaps at one side thereof and changes the angular relation of said one side and so that the other tool widens the gaps at the other side thereof and corre-- 

